Semiconductor light emitting device and method for manufacturing the same

ABSTRACT

Provided is a semiconductor light emitting device  1  includes a semiconductor stacked layer  2  having a light extraction surface  3   a  perpendicular to a stacked surface of the semiconductor stacked layer  2,  a light transmissive light guide member  3  disposed on the semiconductor stacked Layer  2,  a light reflective member  4  disposed on the light guide member  3,  and a light reflective package  5  which has an open portion corresponding to the light extraction surface  3   a  and surrounds peripheral surfaces of the semiconductor stacked layer  2.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 USC 119 from Japanese patentApplication No. 2013-236935, filed on Nov. 15, 2013, the disclosures ofwhich are incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates to a semiconductor light emitting deviceand a method for manufacturing the semiconductor light emitting device.

2. Description of the Related Art

A light emitting diode (hereinbelow, referred to as “LED”) is employedas a light source in a lighting device arid various application productssuch as an optical communication device and a portable electronic devicebecause of its high luminous efficiency, low power consumption, and longlife. In a present mainstream white LED, white light formed only by asingle LED element (single chip) is achieved on the basis of acombination of a blue LED having a wavelength peak of around 450 nm anda yellow phosphor which converts the wavelength of blue light into awavelength of around 550 nm.

In recent years, remarkable progress has been made in downsizing andimprovement in performance, for example, in a portable electronicdevice. Accordingly, a semiconductor light emitting device having asmaller size and higher luminance that can be mounted on such a deviceis required. A downsized semiconductor light emitting device is widelyused as a so-called chip size package (CSP). For example, WO 2010/044240discloses a light emitting module that is provided with a light emittingelement, a light wavelength conversion member which converts thewavelength of light emitted from the light emitting element, and a lightguide member which narrows down the exit area of light that has passedthrough the light wavelength conversion member so as to be smaller thanthe light emission area of the light emitting element. The lightemitting module is capable of increasing the luminance by reducing the,exit area of light.

SUMMARY

A semiconductor light emitting device includes a semiconductor stackedlayer having a light extraction surface perpendicular to a stackedsurface of the semiconductor stacked layer; a light transmissive lightguide member disposed on the semiconductor stacked layer; a lightreflective member disposed on the light guide member; and a lightreflective package that has an open portion corresponding to the lightextraction surface and surrounds peripheral surfaces of thesemiconductor stacked layer.

The semiconductor light emitting device can achieve downsizing and highluminance by employing a structure capable of increasing the lightemission intensity without increasing the area of a light extractionsurface.

BRIEF DESCRIPTION TH DRAWINGS

FIG. 1 is a diagram schematically showing a cross section of asemiconductor light emitting device according to an embodiment of thepresent invention.

FIG. 2 is a front view of the semiconductor light emitting device shownin FIG. 1 viewed from a light extraction surface.

FIG. 3 is a cross-sectional view of a semiconductor light emittingdevice; according to a first embodiment of the present invention.

FIGS. 4A to 4E are diagrams for explaining a method for manufacturingthe semiconductor light emitting device shown in FIG. 3.

FIG. 5 is a cross-sectional view of a semiconductor light emittingdevice according to a second embodiment of the present invention.

FIG. 6 is a cross-sectional view of semiconductor light emitting deviceaccording to a third embodiment of the present invention.

FIG. 7 is a cross-sectional view of a semiconductor light emittingdevice according to a fourth embodiment of the present invention.

FIG. 8 is a cross-sectional view of a semiconductor light emittingdevice according to a fifth embodiment of the present invention.

FIG. 9 is a cross-sectional view of a semiconductor light emittingdevice according to a sixth embodiment of the present invention.

FIG. 10 is a cross-sectional view of a semiconductor light emittingdevice according to a seventh embodiment of the present invention.

FIG. 11 is a cross-sectional view of a semiconductor light emittingdevice according to an eighth embodiment of the present invention.

FIG. 12 is a perspective view of the semiconductor light emitting deviceshown in FIG. 11.

DETAILED DESCRIPTION OF EMBODIMENTS

In a conventional semiconductor light emitting device, it is necessaryto increase the area of a light extraction surface in order to increasethe light emission intensity. Therefore, downsizing of a light emittingdevice having high luminance has been considered to be difficult.

The embodiment of the present invention has been made in view of such aconventional problem, and an object thereof is to provide asemiconductor light emitting device that achieves downsizing and highluminance by employing a structure capable of increasing the lightemission intensity without increasing the area of a light extractionsurface and a method of manufacturing the semiconductor light emittingdevice. The present invention includes following embodiments.

The embodiment of the present invention provides a semiconductor lightemitting device that includes a semiconductor stacked layer having alight extraction surface perpendicular to a stacked surface of thesemiconductor stacked layer, a light transmissive light guide memberdisposed on the semiconductor stacked layer, a light reflective memberdisposed on the light guide member, and a light reflective package thathas an open portion corresponding to the light extraction surface andsurrounds at least a portion of peripheral surfaces of the semiconductorstacked layer.

Further, the present embodiment provides a method for manufacturing asemiconductor light emitting device that includes a light extractionsurface perpendicular to a stacked surface of a semiconductor stackedlayer. The method includes arranging a plurality of light emittingelements each having a semiconductor layer and electrodes so that theelectrodes are in contact with a sheet, arranging a light guide memberhaving a light reflective member fanned on one surface thereof over andacross at least two adjacent ones of the plurality of light emittingelements, arranging a light reflective insulating member to fill a gapbetween the plurality of light emitting elements, and cutting theinsulating member and the light guide member at a position between theat least two adjacent light emitting elements.

The present embodiment makes it possible to increase the light emissionintensity without increasing the area of a light extraction surface in asemiconductor light emitting device.

By employing the structure as described above, it is possible to achievethickness reduction and high luminance of a semiconductor light emittingdevice. For example, it is possible to increase the area of asemiconductor light emitting layer in the depth direction whilemaintaining the size of a light extraction surface of a semiconductorlight emitting device and thereby achieve high luminance.

Hereinafter, embodiments of the present invention will be described withreference to the drawings. Identical elements and elements havingdifferent forms, but having a corresponding relationship will be denotedby the same reference marks throughout the drawings to be referred to.The configurations in these drawings are merely examples for explainingthe semiconductor light emitting device of the present invention.Further, the drawings are schematic views illustrating members of thesemiconductor light emitting device in an exaggerated manner. Therefore,the present invention is not limited to these drawings and thedescription of the embodiments.

FIG. 1 is a diagram schematically showing a cross section of asemiconductor light emitting device 1 according to an embodiment of thepresent invention. FIG, 2 is a front view of the semiconductor lightemitting device 1 shown in FIG. 1 viewed from a light extractionsurface.

The semiconductor light emitting device 1 includes a semiconductorstacked layer 2 which is an LED and a light extraction surface 3 a forextracting light emitted from the semiconductor stacked layer 2 to theoutside. The light extraction surface 3 a may be substantiallyperpendicular to the semiconductor stacked layer 2. When the lightextraction surface 3 a is perpendicular at least to an active layer (p-njunction layer) which is an intermediate layer of the semiconductorstacked layer 2, the light extraction surface 3 a can be regarded asbeing perpendicular or substantially perpendicular to the semiconductorstacked layer 2.

For example, a GaN-based LED which is composed of a nitride-basedcompound semiconductor (represented by a general formula ofIn_(x)Al_(y)Ga_(1-x-y)N (0≦x, 0≦y, x+y≦1) can be used as thesemiconductor stacked layer 2. Examples of a GaN-based LED include anultraviolet LED, a blue LED, a green LED, and the like. Thesemiconductor stacked layer 2 which constitutes an LED may be composedof another compound semiconductor such as a ZnSe-based compoundsemiconductor, an InGaAs-based compound semiconductor, and anAlInGaP-based compound semiconductor. In this case, the wavelength handof color of light emitted from the LED may be the entire region from,ultraviolet light to visible light.

The semiconductor stacked layer 2 may be formed, for example, by a metalorganic chemical vapor deposition (MOCVD) method by sequentiallystacking layers on a growth substrate such as a sapphire substrate.Further, the semiconductor stacked layer 2 may also be formed by anothervapor or liquid phase deposition method.

Further, the semiconductor light emitting device 1 includes a lighttransmissive light guide member 3 disposed on the semiconductor stackedlayer 2, a light reflective member 4 disposed on the light guide member3, and a light reflective package 5 which has an open portioncorresponding to the light extraction surface 3 a and surroundsperipheral surfaces of the semiconductor stacked layer 2. The package 5may cover the upper surface of the light reflective member 4.

The light transmissive light guide member 3 may be, for example, a glasssubstrate. The light guide member 3 may have a single layer structureand may also have a multilayer structure which includes a transparentportion 31 and a wavelength conversion portion 32 which converts thewavelength of light emitted from the semiconductor stacked layer 2 andincludes, for example, a phosphor, the wavelength conversion portion 32and the transparent portion 31 being stacked. For example, the lightguide member 3 may be a glass substrate having a phosphor layer formedon one surface thereof.

The light guide member 3 may seal the semiconductor stacked layer 2.Such a sealing member is preferably composed of a resin containing aphosphor. The sealing member may not necessarily contain a phosphor, andmay be a resin that contains a diffusing material (filler or the like)or a coloring material (a pigment or the like).

The light guide member 3 may be disposed in contact with thesemiconductor stacked layer 2, and may also be disposed on thesemiconductor stacked layer 2 with a certain kind of medium layer suchas a transparent adhesive layer interposed therebetween. Further, thelight guide member 3 may also be disposed on the semiconductor stackedlayer 2 with a growth substrate such as a sapphire substrate that isused for forming the semiconductor stacked layer 2 interposedtherebetween.

The light reflective member 4 is preferably a DBR (Distributed BraggReflector) which is formed on the surface of the light guide member 3.The DBR is a diffraction grating having a spatial period of λ/2n(wherein 2 denotes the wavelength of light in vacuum, and n denotes therefractive index of a medium (specifically, the light guide member)).The light reflective member 4 which is the DBR has a function ofreflecting light, emitted from the semiconductor stacked layer 2 towardthe light guide member 3. Accordingly, light emitted from thesemiconductor stacked layer 2 is efficiently guided to the lightextraction surface 3 a through the light guide member 3.

The light reflective member 4 may be formed of metal having lightreflectivity or glossiness such as Ag and Al. The light reflectivemember 4 may be a stacked body of a metal layer and a DBR layer.

The package 5 is preferably formed of a thermosetting resin such as asilicone resin and an epoxy resin. The package 5 may be formed of anelectrically insulating material. The thermosetting resin preferablyincludes one kind of oxide selected from the group consisting of Tioxide, Zr oxide, Nb oxide, Al oxide, and Si oxide or at least oneselected from AlN and MgF. In particular, at least one selected from thegroup consisting of TiO₂, ZrO₂, Nb₂O₅, Al₂O₃, MgF, AlN, and SiO₂ ispreferably mixed with the thermosetting resin. By employing thesematerials, it is possible to impart preferred electrically insulatingproperty, mechanical strength, and light reflectivity to the package 5.

As the package 5, a thermoplastic resin that can be transfer-molded maybe used in addition to the above resins.

The package 5 having both light reflectivity and electrically insulatingproperty as described above may be integrated with an insulating memberwhich electrically insulates an n-electrode 11 and a p-electrode 12 bothconnected to the semiconductor stacked layer 2. Accordingly thestructure of the semiconductor light emitting device 1 is simplified,and the number of manufacturing processes is reduced.

The light extraction surface 3 a of the semiconductor light emittingdevice 1 includes the end surface of the transparent portion 31 and theend surface of the wavelength conversion portion 32. Further, an endpart of the semiconductor stacked layer 2 the end part corresponding tothe light extraction surface 3 a, is covered with the package 5.Therefore, light emitted from the end part of the semiconductor stackedlayer 2 corresponding to the light extraction surface 3 a is suppressed,As a result, color unevenness can be suppressed.

First Embodiment

FIG. 3 is a cross-sectional view of a semiconductor light emittingdevice according to a first embodiment of the present invention. Asemiconductor light emitting device 1 includes a semiconductor stackedlayer 2 which constitutes an LED as a light emitting element, and ann-electrode 11 and p-electrode 12 each formed on the lower surface ofthe semiconductor stacked layer 2. The n-electrode 11 is disposed behindthe p-electrode 12 as shown in FIG. 2.

As shown in FIG. 3, the semiconductor light emitting device 1 emitslight in such a manner that a forward current is supplied to thesemiconductor stacked layer 2 to thereby move carriers to an activelayer 23 so as to be trapped therein and recombination of the carriersefficiently occurs in the active layer 23. The active layer 23 is alsocalled a light emitting layer. In the semiconductor stacked layer 2, ann-type semiconductor layer 21, the active layer 23, and a p-typesemiconductor layer 22 are stacked in this order on a growth substrate30. The active layer 23 has a quantum well structure. In the presentembodiment, a nitride semiconductor is used as the semiconductor stackedlayer 2.

For example, the n-type semiconductor layer 21 includes a GaN layer thatcontains Si, and the p-type semiconductor layer 22 includes a GaN layerthat contains Mg or Zn. The active layer 23 includes a GaN layer or anInGaN layer. The active layer 23 emits blue light.

The n-electrode 11 as a cathode of the LED is electrically joined to then-type semiconductor layer 21. On the other hand, the p-electrode 12 asan anode of the LED is electrically joined to the p-type semiconductorlayer 22. For example, an under barrier metal (UBM) film is formed at apredetermined position in each of the n-type semiconductor layer 21 andthe p-type semiconductor layer 22 by sputtering or the like and theformed UBM film is then plated with conductive metal with excellentwettability, for example, Au, thereby obtaining the n-electrode 11 andthe p-electrode 12 in a bump form.

In order to achieve an LED having higher luminance, a light reflectivelayer (not illustrated) may be disposed on the lower surface of thep-type semiconductor layer 22. The light reflective layer may be, forexample, a DBR that is formed as a part of the p-type semiconductor.That is, the light reflective layer which is composed of the DBR candiffract light that has been emitted from the active layer 23 toward theelectrodes 11, 12 to the opposite side and supply a forward current tothe active layer 23 and the n-type semiconductor layer 21. Further, ametal layer having high reflectivity such as an Ag layer and an Al layercan be used as the light reflective layer. Such a metal layer can serveas a part of the p-electrode 12.

A light extraction surface 3 a of the semiconductor light emittingdevice 1 is formed on one side surface of the semiconductor lightemitting device 1 so as to be perpendicular to the semiconductor stackedlayer 2. A light transmissive light guide member 3 is disposed on thesemiconductor stacked layer 2 with the growth substrate (sapphiresubstrate) 30 interposed therebetween. As another form of thesemiconductor light emitting device 1, the light guide member 3 may bedisposed in contact with the semiconductor stacked layer 2 after thegrowth substrate 30 is removed by a laser lift off (LLO) method.

The light guide member 3 includes a transparent portion 31 which is atransparent glass substrate, and a wavelength conversion portion 32which is a phosphor layer. In the present embodiment, the phosphor layeris formed on one surface of the alas substrate in the light guide member3.

The wavelength conversion portion 32 may contain, for example, anitride-based or oxynitride-based phosphor activated by alanthanoid-based element such as Ce and Eu. More specifically, forexample, a rare earth aluminate phosphor activated by a lanthanoid-basedelement such as Ce may be used as the phosphor, and a YAG based phosphoris preferably used. In the YAG-based phosphor, a part or the entire of Ymay be substituted with Tb or Lu. Further, Ce-activated rare earthsilicate may be used as the material of the phosphor.

Further, alkaline earth halogen apatite, alkaline earth metal boratehalogen, alkaline earth metal aluminate alkaline earth metal sulfide,alkaline earth metal thiogallate, alkaline earth metal silicon nitride,or alkaline earth metal germanate activated by a lapthanoid-basedelement such as Eu, or an organic body or an organic complex activatedby a lanthanoid-based element such as Eu may be used as the material ofthe phosphor. Examples of a red phosphor include a SCASN-based phosphorsuch as (Sr, Ca)AlSiN₃:Eu, a CASN-based phosphor such as CaAlSiN₃:Eu,and SrAlSiN₃:Eu In addition to the above, a phosphor that absorbs bluelight emitted from a light emitting element and emits green light, forexample, a chlorosilicate phosphor or a β-sialon phosphor may be used asthe material. Further, the material may be at least one selected fromthe group consisting of a Mn⁴⁺ activated Mg fluorogermanate phosphor anda M¹ ₂M²F₆:Mn¹=Li, Na, K, Rb, Cs; M²=Si, Ge, Sn, Ti, Zr) phosphor.

The semiconductor light emitting device 1 includes a light reflectivemember 4 which is disposed on the light guide member 3. The lightreflective member 4 is a DBR which is formed on the surface of thewavelength conversion portion 32 of the light guide member 3. The lightreflective member 4 may also be metal having light reflectivity orglossiness such as Ag and Al. The light reflective member 4 may also bea stacked body of metal and a DBR.

The semiconductor light emitting device 1 includes a package 5 which hasan open portion corresponding to the light extraction surface 3 a andsurrounds peripheral surfaces of the semiconductor stacked layer 2. Thematerial of the package 5 is an electrically insulating thermosettingresin such as a silicone resin and an epoxy resin. The material of thepackage 5 includes one kind of oxide selected from the group consistingof Ti oxide, Zr oxide, Nb oxide, Al oxide, and Si oxide or at least oneselected from AlN and MgF so that the package 5 has a light reflectivewhite color. In particular, at least one selected from the groupconsisting of TiO₂, ZrO₂, Nb₂O₅, Al₂O₃MgF, AlN, and SiO₂ is preferablymixed with the resin. These resin materials can impart preferredelectrically insulating property, mechanical strength, and lightreflectivity to the package 5.

The semiconductor light emitting device 1 includes the light reflectivemember 4 disposed on the light guide member 3, and the light reflectivepackage 5 which has the open portion corresponding to the lightextraction surface 3 a and surrounds the peripheral surfaces of thesemiconductor stacked layer 2. Accordingly, light emitted from thesemiconductor stacked layer 2 is reflected by the light reflectivemember 4 and the package 5, and efficiently guided to the lightextraction surface 3 a through the light guide member 3. As a result,the semiconductor light emitting device 1 that achieves downsizing andhigh luminance is provided. Further, by increasing the light emissionarea in the semiconductor stacked layer 2 in the lateral direction, itis possible to increase the light emission intensity. Therefore, it ispossible to increase luminous fluxes to be emitted without increasingthe area of the light extraction surface 3 a.

In the embodiments of the present specification, the semiconductor lightemitting device that includes the package having a dimension of 2 mm×1mm and a thickness of 0.3 mm is used. However the dimension of thepackage is not particularly limited.

Next, a method for manufacturing the semiconductor light emitting deviceof the first embodiment will be described with reference to FIGS. 4A to4E.

First, a plurality of light emitting elements 40 are prepared. In eachof the light emitting elements 40, the semiconductor stacked layer 2which is an LED, the n-electrode 11, the p-electrode 12, a predeterminedprotective film layer, and the like are formed on the growth substrate30. The semiconductor stacked layer 2 is formed of a nitride-basedsemiconductor such as GaN. A sapphire single crystal substrate is usedas the growth substrate 30.

The plurality of light emitting elements 40 are placed on an adhesivesheet 41 so that the growth substrates 30 face upward and then-electrodes 11 and the p-electrodes 12 are in contact with the adhesivesheet 41 (FIG. 4A). Then, the light guide member 3 is disposed on thegrowth substrate 30 (FIG. 4B). In the light guide member 3, the lightreflective member 4 is previously formed on a surface opposite to asurface on which the light emitting element 40 is disposed. In the lightguide member 3 of the present embodiment, the wavelength conversionportion 32 which includes a YAG-based phosphor is stacked on thetransparent portion 31 which is a transparent glass substrate. Further,a DBR as the light reflective member 4 is formed on the surface of thewavelength conversion portion 32.

In another embodiment, the light guide member is disposed on the growthsubstrate over and across at least two adjacent light emitting elements.

Then, a light reflective insulating member 51 is disposed to fill a gapbetween the plurality of light emitting elements 40 (FIG. 4C). Theinsulating member 51 is the material of the package 5. The insulatingmember 51 is a silicone thermosetting resin mixed with at least oneselected from the group consisting of TiO₂, ZrO₂, Nb₂O₅, Al₂O₃, MgF,AlN, and SiO₂. The insulating member 51 is also filled into a gapbetween the electrodes 11, 12 in order to insulate the electrodes 11, 12of the light emitting element 40.

As a method for molding the insulating member 51, a general moldingmethod such as a compression molding method, a transfer molding method,and an injection molding method can be employed. After curing theinsulating member 51 by heating, pad electrodes 42 which areelectrically connected to the electrodes 11, 12 of the light emittingelements 40 may be optionally formed (FIG. 4D).

Then, the insulating member 51 and the light guide member 3 are cut at aposition between at least two adjacent light emitting elements 40 (FIG.4E). As a method for cutting the insulating member 51 and the lightguide member 3, for example, dicing or diamond cut is used. Thesemiconductor light emitting device 1 that achieves downsizing and highluminance is provided through the manufacturing processes as describedabove.

The light extraction surface 3 a of the semiconductor light emittingdevice 1 includes the end surface of the transparent portion 31 and theend surface of the wavelength conversion portion 32. Further, in a casethat an end part of the semiconductor stacked layer 2, the end partcorresponding to the light extraction surface 3 a, is covered with theinsulating member 51, light emitted from the end part of thesemiconductor stacked layer 2 corresponding to the light extractionsurface 3 a is suppressed. As a result, color unevenness can besuppressed.

Second Embodiment

FIG. 5 is a cross-sectional view of a semiconductor light emittingdevice according to a second embodiment of the present invention. Asemiconductor light emitting device 1 includes a semiconductor stackedlayer 2 which constitutes an LED as a light emitting element, and ann-electrode 11 and p-electrode 12 each formed on the lower surface ofthe semiconductor stacked layer 2. A pad electrode may be formed incontact with the n-electrode 11 and the p-electrode 12. In FIG. 5, then-electrode 11 is disposed behind the p-electrode 12 as shown in FIG. 2.

A light extraction surface of the semiconductor light emitting device 1is formed on one side surface of the semiconductor light emitting device1 so as to be perpendicular to the semiconductor stacked layer 2. Alight guide member 3 which includes a transparent portion 31 and awavelength conversion portion 32, is disposed on the semiconductorstacked layer 2 with a growth substrate 30 interposed therebetween. Thetransparent portion 31 is a transparent glass substrate. The wavelengthconversion portion 32 is a YAG -based phosphor. In the presentembodiment, as illustrated in FIG. 5, the transparent portion 31 of thelight guide member 3 is in contact with the growth substrate 30.

A light reflective member 4 is disposed on the light guide member 3. Thelight reflective member 4 includes two layers, specifically, a metallayer 46 which contains a metallic element having light reflectivity orglossiness such as Ag and Al and a DBR 47. In the embodiment illustratedin FIG. 5 the metal layer 4 is disposed on the surface of the wavelengthconversion portion (YAG) 32 with the DBR 47 interposed therebetween. Themetal layer 46 may be directly disposed on the surface of the wavelengthconversion portion (YAG) 32 without the DBR interposed therebetween.

The semiconductor light emitting device 1 includes a package 5 which hasan open portion corresponding to the light extraction surface andsurrounds peripheral surfaces of the semiconductor stacked layer 2, thelight guide member 3, and the light reflective member 4, The material ofthe package 5 is an electrically insulating thermosetting resin such asa silicone resin, At least one selected from the group consisting ofTiO₂, ZrO₂, Nb₂O₅, Al₂O₃, MgF, AlN, and SiO₂ is mixed with thethermosetting resin of the package 5. These resin materials can impartpreferred electrically insulating property, mechanical strength, andlight reflectivity to the package 5.

The semiconductor light emitting device 1 according to the secondembodiment includes the light reflective package 5 which has the openportion corresponding to the light extraction surface and surrounds theperipheral surfaces of the semiconductor stacked layer 2, the lightguide member 3, and the light reflective member 4. Accordingly, lightemitted from the semiconductor stocked layer 2 is reflected by the lightreflective member 4 and the package 5, and efficiently guided to thelight extraction surface through the light guide member 3. As a result,the semiconductor light emitting device that achieves downsizing andhigh luminance is provided. Further, by increasing the light emissionarea in the semiconductor stacked layer 2 in the lateral direction, itis possible to increase the light emission intensity. Therefore, it ispossible to increase luminous fluxes to be emitted without increasingthe area of the light extraction surface.

An end part of the semiconductor stacked layer 2, the end partcorresponding to the light extraction surface 3 a, is covered with theinsulating member 5. Therefore, light emitted from the end part of thesemiconductor stacked layer 2 corresponding to the light extractionsurface 3 a is suppressed. As a result, color unevenness can besuppressed.

In the light guide member 3 described above, the transparent portion 31and the wavelength conversion portion 32 are stacked in this order onthe growth substrate 30, In the light reflective member 4, the DBR 47and the metal layer 46 are stacked in this order on the wavelengthconversion portion 32.

Third Embodiment

FIG. 6 is a cross-sectional view of a semiconductor light emittingdevice according to a third embodiment of the present invention. Asemiconductor light emitting device 1 includes a semiconductor stackedlayer 2 which constitutes an LED as a light emitting element, and ann-electrode 11 and p-electrode 12 each formed on the lower surface ofthe semiconductor stacked layer 2. A pad electrode may be formed incontact with the n-electrode 11 and the p-electrode 12. In FIG. 6, then-electrode 11 is disposed behind the p-electrode 12, as shown in FIG.2.

A light extraction surface of the semiconductor light emitting device 1is formed on one side surface of the semiconductor light emitting device1 so as to be perpendicular to the semiconductor stacked layer 2.Further, the semiconductor light emitting device 1. includes a package 5which has an open portion corresponding to the light extraction surfaceand surrounds peripheral surfaces of the semiconductor stacked layer 2,a light guide member 3, and a light reflective member 4. The material ofthe package 5 is an electrically insulating thermosetting resin such asa silicone resin. At least one selected from the group consisting ofTiO₂, ZrO₂, Nb₂O₅, Al₂O₃, MgF, AlN, and SiO₂ is mixed with thethermosetting resin of the package 5.

The light guide member which includes a transparent portion 31 and awavelength conversion portion 32 is disposed, on the semiconductorstacked layer 2 after a growth substrate (not illustrated) is removed bya laser lift off (LLO) method. The transparent portion 31 is atransparent glass substrate. The wavelength conversion portion 32 is aYAG-based phosphor. In the present embodiment, as illustrated in FIG. 6,the transparent portion 31 of the light guide member 3 is in contactwith the semiconductor stacked layer 2.

The light reflective member 4 is disposed on the light guide member 3.The light reflective member 4 is a stacked body of a DBR 47 and a metallayer 46 which contains a metallic element having light reflectivity orglossiness such as Ag and Al. In the embodiment illustrated in FIG. 6,the metal layer 46 is disposed on the surface of the wavelengthconversion portion (YAG) 32 with the DBR 47 interposed therebetween. Themetal layer 46 may be directly disposed on the surface of the wavelengthconversion portion (YAG) 32 without the DBR interposed therebetween.

In the package 5, a width X between e end of the semiconductor stackedlayer 2 and the end of the package 5 on the side corresponding to thelight extraction surface is several pan or more, and preferably 30 ormore. For example, in the present embodiment, the width X is 50 μm. Awidth Y between the end of the semiconductor stacked layer 2 and the endof the package 5 on the side opposite to the light extraction surface is50 μm or more, and preferably 100 μm or more. thickness Z of the package5 above the light reflective member 4 is preferably 5 μm or more.Accordingly, it is possible to achieve higher luminance in thesemiconductor light emitting device.

In the semiconductor light emitting device 1 according to the thirdembodiment, an insulating member continuously covers the end part of thesemiconductor stacked layer 2 through the upper surface of the metallayer 46. Therefore, it is possible to suppress light leaking to theupper side of the semiconductor light emitting device 1.

The semiconductor light emitting device 1 according to the thirdembodiment includes the light reflective package 5 which has the openportion corresponding to the light extraction surface and surrounds theperipheral surfaces of the semiconductor stacked layer 2, the lightguide member 3, and the light reflective member 4. Accordingly, lightemitted from the semiconductor stacked layer 2 is reflected by the lightreflective member 4 and the package 5, and efficiently guided to thelight extraction surface through the light guide member 3. As a result,the semiconductor light emitting device that achieves downsizing andhigh luminance is provided. Further, by increasing the light emissionarea in the semiconductor stacked layer 2 in the lateral direction, itis possible to increase the light emission intensity. Therefore, it ispossible to increase luminous fluxes to be emitted without increasingthe area of the light extraction surface. More specifically, it ispossible to increase the area of the semiconductor light emitting layerin the depth direction while maintaining the size of the lightextraction surface of the semiconductor light emitting device andthereby achieve high luminance.

Fourth Embodiment

FIG. 7 is a cross-sectional view of a semiconductor light emittingdevice according to a fourth embodiment of the present invention. Asemiconductor light emitting device 1 includes a semiconductor stackedlayer 2 which constitutes an LED as a light emitting element, and ann-electrode 11 and p-electrode 12 each formed on the lower surface ofthe semiconductor stacked layer 2. A pad electrode may be formed incontact with the n-electrode 11 and the p-electrode 12. In FIG. 7, then-electrode 11 is disposed behind the p-electrode 12 as shown in FIG. 2.

A light extraction surface of the semiconductor light emitting device 1is formed on one side surface of the semiconductor light emitting device1 so as to be perpendicular to the semiconductor stacked layer 2.Further, the semiconductor light emitting device 1 includes a package, 5which has an open portion corresponding to the light extraction surfaceand surrounds peripheral surfaces of the semiconductor stacked layer 2,a light guide member 3, and a metal layer 46. The material of thepackage 5 is an electrically insulating thermosetting resin such as asilicone resin. At least one selected from the group consisting of TiO₂,ZrO₂, Nb₂O₅, Al₂O₃, MgF, AlN, and SiO₂ is mixed with the thermosettingresin of the package 5. These resin materials can impart preferredelectrically insulating property, mechanical strength, and lightreflectivity to the package 5.

The light guide member 3 which includes a transparent portion 31 and awavelength conversion portion 32 is disposed on the semiconductorstacked layer 2 after a growth substrate (not illustrated) is removed byan LLO method. The transparent portion 31 is a transparent glasssubstrate. The wavelength conversion portion 32 is a YAG-based phosphor.In the present embodiment, as illustrated in FIG. 7, the metal layer 46which contains a metallic element having light reflectivity orglossiness such as Ag and Al is formed on the transparent portion (glasssubstrate) 31 by an electroless plating method or the like. A DBR (notillustrated) may be formed on the transparent portion (glass substrate)31, and the metal layer 46 may be formed on the DBR.

The wavelength conversion portion (YAG) 32 is adhered to thesemiconductor stacked layer 2 with an adhesive layer 61 interposedtherebetween. The adhesive layer 61 is formed of a transparent resinmaterial.

The semiconductor light emitting device 1 according to the fourthembodiment includes the light reflective package 5 which has the openportion corresponding to the light extraction surface and surrounds theperipheral surfaces of the semiconductor stacked layer 2, the lightguide member 3, and the metal layer 46. Accordingly, light emitted fromthe semiconductor stacked layer 2 is reflected by the metal layer 46 andthe package 5, and efficiently guided to the light extraction surfacethrough the light guide member 3. As a result, the semiconductor lightemitting device that achieves downsizing and high luminance is provided.Further, by increasing the light emission area in the semiconductorstacked layer 2 in the lateral direction, it is possible to increase thelight emission intensity. Therefore, it is possible to increase luminousfluxes to be emitted without increasing the area of the light extractionsurface.

Fifth Embodiment

FIG. 8 is a cross-sectional view of a semiconductor light emittingdevice according to a fifth embodiment of the present invention. Asemiconductor light emitting device 1 includes a semiconductor stackedlayer 2 which constitutes an LED as a light emitting element, and ann-electrode 11 and p-electrode 12 each formed on the lower surface ofthe semiconductor stacked layer 2. A pad electrode may be formed incontact with the n-electrode 11 and the p-electrode 12. In FIG. 8, then-electrode 11 is disposed behind the p-electrode 12 as shown in FIG. 2.

A light extraction surface of the semiconductor light emitting device isformed on one side surface of the semiconductor light emitting device 1so as to be perpendicular to the semiconductor stacked layer 2. Further,the semiconductor light emitting device 1 includes a package 5 which hasan open portion corresponding to the light extraction surface andsurrounds peripheral surfaces of the semiconductor stacked layer 2, awavelength conversion portion 32, and a light reflective member 4. Thematerial of the package 5 is an electrically insulating thermosettingresin such as a silicone resin. At least one selected from the groupconsisting of TiO₂, Nb₂O₅, Al₂O₃, MgF, AlN, and SiO₂ is mixed with thethermosetting resin of the package 5.

The wavelength conversion portion 32 which is a YAG-based phosphor isdisposed on the semiconductor stacked layer 2 with a growth substrate 30interposed therebetween. In the present embodiment, as illustrated inFIG. 8, the wavelength conversion portion 32 is directly joined to thegrowth substrate 30 of the semiconductor stacked layer 2. Here, “directjoining” indicates that surfaces to be joined are joined by atomic bondwithout using an adhesive. Direct joining that can be used here ispreferably a joining method that is generally classified asroom-temperature joining. Direct joining also includes a method thataccelerates a chemical reaction or diffusion for joining at an extremelyhigh temperature. However, such a method is not preferred in LEDproduction of the present invention because of temperature limitation.For example, there is also an anode joining method that performs joiningby applying not temperature, but an electric field. However, such amethod is also not preferred because there is concern about a surfacelayer material that is required for applying an electric field and theinfluence on the semiconductor.

Examples of a direct joining method suitable for the present embodimentinclude surface activation joining, atomic diffusion joining, andhydroxyl group joining, In surface activation joining, inert ions areapplied to the joining interface in ultrahigh vacuum to thereby cleanand activate the surface to perform joining. In atomic diffusionjoining, metal is sputtered also in ultrahigh vacuum and joining isperformed using diffusion of the metal. It has been confirmed that, bymaking the sputtered film extremely thin, the joining can be performedwithout affecting extraction of light. In hydroxyl group joining, ahydroxyl group is formed on the joining interface and joining isperformed using hydrogen bond of the hydroxyl group. The above threejoining methods are all room-temperature joining methods. However, abonding power may increase by performing heat treatment as needed. Inthis case, heating can be performed at 400° C. or less, preferably at300° C. or less, and more preferably at 200° C. or less.

Further, “direct joining” indicates that different kinds of materialsare joined without an organic material such as an adhesive interposedtherebetween. Even when metal or a dielectric substance is introduced asan intermediate member, the optical characteristic of the intermediatemember is ignored when introducing light into a joining member. As thejoining member, for example, a YAG phosphor can be used.

The light reflective member 4 is disposed on the wavelength conversionportion 32, The light reflective member 4 includes two layers,specifically, a DBR 47 and a metal layer 46 which contains a metallicelement having light reflectivity or glossiness such as Ag and Al. Inthe present embodiment, as illustrated in FIG. 8, the metal layer 46 isdisposed on the surface of the wavelength conversion portion (YAG) 32with the DBR 47 interposed therebetween. The metal layer 46 may hedirectly disposed on the surface of the wavelength conversion portion(YAG) 32 without the DBR 47 interposed therebetween.

The semiconductor light emitting device 1 according to the fifthembodiment includes the light reflective package 5 which has the openportion corresponding to the light extraction surface and surrounds theperipheral surfaces of the semiconductor stacked layer 2, the wavelengthconversion portion (YAG) 32, and the light reflective member 4.Accordingly, light emitted from the semiconductor stacked layer 2 isreflected by the light reflective member 4 and the package 5, thenwavelength-converted by the wavelength conversion portion (YAG) 32, andthen efficiently guided to the light extraction surface. As a result,the semiconductor light emitting device that achieves downsizing andhigh luminance is provided. Further, by increasing the light emissionarea in the semiconductor stacked layer 2 in the lateral direction, itis possible to increase the light emission intensity. Therefore, it ispossible to increase luminous fluxes to be emitted without increasingthe area of the light extraction surface.

Sixth Embodiment

FIG. 9 is a cross-sectional view of a semiconductor light emittingdevice according to a sixth embodiment of the present invention. Asemiconductor light emitting device I includes a semiconductor stackedlayer 2 which constitutes an LED as a light emitting element, and ann-electrode 11 and p-electrode 12 each formed on the lower surface ofthe semiconductor stacked layer 2. A pad electrode may be formed incontact with the n-electrode 11 and the p-electrode 12. In FIG. 9, then-electrode 11 is disposed behind the p-electrode 12 as shown in FIG. 2.

A light extraction surface of the semiconductor light emitting device 1is formed on one side surface of the semiconductor light emitting device1 so as to be perpendicular to the semiconductor stacked layer 2. In thesemiconductor light emitting device 1, a BPF (Band Pass Filter) 33 whichhas an open portion corresponding to the light extraction surface, awavelength conversion portion 32, and a light reflective member 4 arestacked in this order on the semiconductor stacked layer 2. Further, thesemiconductor light emitting device 1 includes a package 5 whichsurrounds outer peripheral surfaces of the light reflective member 4.The above-described resins can be used as the material of the package 5.

The wavelength conversion portion 32 which is a YAG-based phosphor isdisposed on a growth substrate 30 of the semiconductor stacked layer 2with the BPF 33 interposed therebetween. The BPF 33 is an optical filterthat transmits light having a wavelength band of for example, 420 to 500nm. The wavelength band of the BPF 33 is preferably 430 to 470 nm. Apeak of the LED that is composed of the nitride-based semiconductorstacked layer 2 is 450 nm.

The light reflective member 4 is disposed on the wavelength conversionportion 32. The light reflective member 4 includes two layers,specifically, a DBR 47 and a metal layer 46 which contains a metallicelement having light reflectivity or glossiness such as Ag and Al. Inthe present embodiment, as illustrated in FIG. 9, the metal layer 46 isdisposed on the surface of the wavelength conversion portion (YAG) 32with the DBR 47 interposed therebetween, The metal layer 46 may bedirectly disposed on the surface of the wavelength conversion portion(YAG) 32 without the DBR 47 interposed therebetween.

Seventh Embodiment

FIG. 10 is a cross-sectional view of a semiconductor light emittingdevice according to a seventh embodiment of the present invention. Asemiconductor light emitting device 1 includes a semiconductor stackedlayer 2 which constitutes an LED as a light emitting element, and ann-electrode 11 and p-electrode 12 each formed on the lower surface ofthe semiconductor stacked layer 2. A pad electrode may be formed incontact with the n-electrode 11 and the p-electrode 12. In FIG. 10, then-electrode 11 is disposed behind the p-electrode 12 as shown in FIG. 2.

A light extraction surface of the semiconductor light emitting device 1is formed on one side surface of the semiconductor light emitting device1 so as to be perpendicular to the semiconductor stacked layer 2.Further, the semiconductor light emitting device 1 includes a package 5which has an open portion corresponding to the light extraction surfaceand surrounds peripheral surfaces of the semiconductor stacked layer 2,a BPF 33, a wavelength conversion portion 32, and a light reflectivemember 4. The above-described resins can be used as the, material of thepackage 5.

A light guide member which includes the BPF 33 and the wavelengthconversion portion 32 which is a YAG-based phosphor is disposed on thesemiconductor stacked layer 2 after a growth substrate (not illustrated)is removed by an LLO method in the present embodiment, as illustrated inFIG, 10, the BPF 33 is in contact with the semiconductor stacked layer2.

The BPF 33 is an optical filter that transmits light having a wavelengthband of, for example, 420 to 500 nm. The wavelength band of the BPF 33is preferably 430 to 470 nm. A peak of the LED that is composed of thenitride-based semiconductor stacked layer 2 is 450 nm.

The light reflective member 4 includes two layers, specifically, a DBR47 and a metal layer 46 which contains a metallic element having lightreflectivity or glossiness such as Ag and Al. In the embodimentillustrated in FIG. 10, the metal layer 46 is disposed on the surface ofthe wavelength conversion portion (YAG) 32 with the DBR 47 interposedtherebetween. The metal layer 46 may be directly disposed on the surfaceof the wavelength conversion portion (YAG) 32 with cut the DBR 47interposed therebetween.

Eighth Embodiment

FIG. 11 is a cross-sectional view of a semiconductor light emittingdevice according to an eighth embodiment of the present invention. FIG.12 is a perspective view of the semiconductor light emitting device ofFIG. 11 The semiconductor light emitting device in each of the third toseventh embodiments described above also has the same appearance asillustrated in FIG. 12. A semiconductor light emitting device includes asemiconductor stacked layer 2 which constitutes an LED as a lightemitting element and an n-electrode 11 and p-electrode 12 each formed onthe lower surface of the semiconductor stacked layer 2. In FIG. 11, then-electrode 11 is disposed behind the p-electrode 12 as shown in FIG. 2.

A light extraction surface of the semiconductor light emitting device 1is formed on one side surface of the semiconductor light emitting device1 so as to be perpendicular to the semiconductor stacked layer 2. Apackage 5 of the semiconductor light emitting device 1 has an openportion corresponding to the light extraction surface and houses thesemiconductor stacked layer 2 therein. The semiconductor stacked layer 2housed in the package 5 is sealed by a sealing member 34.

The sealing member 34 is composed of a light transmissive resin thatcontains a YAG-based phosphor. However, the sealing member 34 may notnecessarily contain a phosphor, and may be a resin that contains adiffusing material (a filler or the like) or a coloring material ispigment or the like). The above-described resins can be used as thematerial of the package 5.

The semiconductor light emitting device 1 according to the presentembodiment includes the light reflective package 5 which has the openportion corresponding to the light extraction surface and houses thesemiconductor stacked layer 2 therein. Accordingly, light emitted fromthe semiconductor stacked layer 2 is reflected inside the package 5, andefficiently guided to the light extraction surface through the sealingmember 34. As a result, the semiconductor light emitting device thatachieves downsizing and high luminance is provided. Further, byincreasing the light emission area in the semiconductor stacked layer 2in the lateral direction, it is possible to increase the light emissionintensity. Therefore, it is possible to increase luminous fluxes to beemitted without increasing the area of the light extraction surface.

The present invention is not limited to the specific embodimentsdescribed above. Those skilled in the art can appropriately changenon-essential elements or substitute non-essential elements with otherknown elements in these embodiments within the technical idea disclosedin the present invention.

As described above, it should be obvious that various other embodimentsare possible without departing the spirit and scope of the presentinvention. Accordingly, the scope and spirit of the present inventionshould be limited only by the following claims.

All publications, patent applications, and technical standards mentionedin this specification are herein incorporated by reference to the sameextent as if each individual publication, patent application, ortechnical standard was specifically and individually indicated to beincorporated by reference.

What is claimed is:
 1. A semiconductor light emitting device comprising: a semiconductor stacked layer having a light extraction surface perpendicular to a stacked surface of the semiconductor stacked layer; a light transmissive light guide member disposed on the semiconductor stacked layer; a light reflective member disposed on the light guide member; and a light reflective package that ha an open portion corresponding to the light extraction surface and surrounds at least a portion of peripheral surfaces of the semiconductor stacked layer.
 2. The semiconductor light emitting device according to claim 1, wherein the light reflective package is integrated with an insulating member that electrically insulates electrodes connected to the semiconductor stacked layer.
 3. The semiconductor light emitting device according to claim 1, wherein the light reflective member is formed of metal.
 4. The semiconductor light emitting device according to claim 1, wherein the light reflective member comprises a DBR (Distributed Bragg Reflector).
 5. The semiconductor light emitting device according to claim 1, wherein the light reflective member comprises a DBR formed of metal.
 6. The semiconductor light emitting device according to claim 1, wherein the light guide member comprises a wavelength conversion portion.
 7. The semiconductor light emitting device according to claim 1, wherein the light guide member comprises a wavelength conversion portion and a transparent portion, the wavelength conversion portion and the transparent portion being stacked.
 8. The semiconductor light emitting device according to claim 7, wherein the light guide member is formed of a glass substrate having a phosphor layer formed on one surface thereof.
 9. A method for manufacturing a semiconductor light emitting device that includes a light extraction surface perpendicular to a stacked surface of a semiconductor stacked layer, the method comprising: disposing a plurality of light emitting elements each having a semiconductor layer and electrodes so that the electrodes are in contact with a sheet; disposing a light guide member having a light reflective member formed on one surface thereof over and across at least two adjacent ones of the plurality of light emitting elements; disposing a light reflective insulating member to fill a gap between the plurality of light emitting elements; and cutting the insulating member and the light guide member at a position between the at least two adjacent light emitting elements.
 10. The method for manufacturing a semiconductor light emitting device according to claim 9, further comprising: forming pad electrodes connecting to respective electrodes of each of the plurality of light emitting elements after the arrangement of the light reflective insulating member. 